Disco 2 Alarm

The Alarm went off on my D2 this afternoon. It's been parked up for 3 days on my drive so no obvious reason for it to go off. I used key fob to unlock and re-lock and re-set alarm, however, every time I try to lock it, I get a single horn beep (fob or key). This usually signifies that a door is not shut properly. Having checked opened and closed all doors and bonnet, I still get the single horn beep. So I took it out for a very quick run around the block. I parked up, switched off, locked it ok - no beep. Returned home, parked on my drive and problem is back again. I'm assuming that my battery might be going low and causing it. Any other thoughts or tips on what I should check?
It's unlocked at the moment!

Firstly make sure your battery is in tip top condition, charge it or get it tested

+1 for that^^^ ...if that's ruled out be aware that the fact that all the doors/bonnet are well closed doesnt mean that all the signals from the door switches/bonnet are getting to the BCU, tester is needed to find the open circuit or there is a trick which can rule out only the driver's door, bonnet for sure or one of the other 3 but can't tell which one cos the are all on the same circuit

CliffordGarrett said:

The Alarm went off on my D2 this afternoon. It's been parked up for 3 days on my drive so no obvious reason for it to go off. I used key fob to unlock and re-lock and re-set alarm, however, every time I try to lock it, I get a single horn beep (fob or key). This usually signifies that a door is not shut properly. Having checked opened and closed all doors and bonnet, I still get the single horn beep. So I took it out for a very quick run around the block. I parked up, switched off, locked it ok - no beep. Returned home, parked on my drive and problem is back again. I'm assuming that my battery might be going low and causing it. Any other thoughts or tips on what I should check?
It's unlocked at the moment!

Click to expand...

Try disconnecting each sensor in turn and see if the alarm still trips
Alternately as you disconnect the sensors, check for signal

Dragonwalker said:

Try disconnecting each sensor in turn and see if the alarm still trips
Alternately as you disconnect the sensors, check for signal

Click to expand...

1. which sensors?
2. check for what signal and how?

Try locking the vehicle with the key, I think this should disable the volumetric sensor (the one inside the vehicle that senses air pressure) so you can lock the vehicle with a dog inside etc
We had one last month with a spider inside the sensor; took awhile to find that bugger

Interrogate it with Testbook,this can give the cause of last 5 alarm triggers
While you are at it,you might want to remove the passenger compartment fusebox and check it for water ingress - they dont like it and tend to set off the alarm at random intervals with water in them

it's about an intermittent door or bonnet switch missbehaviour here that's why the misslock audible warning occurs... IMO it has nothing to do with the volumetric alarm, the bonnet switch used to make tricks more often

We had intermittent alarms from water on the back of the volumetric sensors up on the cant rail, corrosion had started through it being live to 12V and that was the issue.





Peter

... and did you get misslock warning on that ??? cos that's the OP's problem

sierrafery said:

... and did you get misslock warning on that ??? cos that's the OP's problem

Click to expand...

We had a multitude of errors coming up, but the random alarm was the most obvious sign of an issue. Knowing the propensity of Discoveries to have water where it shouldn't be, it is worth mentioning as something to check, it is so easily done.

Peter

interesting discussion. I have the battery on charge at the moment so will update in due course.

if you'll get the misslock again, unplug the bonnet switch an bridge the pins in it's plug with a piece of wire then try again... if no misslock this way you have the answer, if no joy i'll tell you more

well, battery charge up and reading 13.5V and the problem 'appears' to have gone away. I do hope the battery holds is charge and alternator keeps charging it!.

if that 13.5V is with engine running the charging system is suspect

No,that was battery out of vehicle.

Bugger! Alarm went off last night. So, I unlocked it with fob and went to bed. I really can't be arsed with it today. I'll have a look tomorrow.

Well, 4 months later, I'm still none the wiser on alarm issues. However, there has been a lot to confuse the issue in that time.
In no particular order:

- Replaced key fob as worn out casing (plastic button broke away). I used a new plastic case but transfered the pcb and key. Mine has no separate transponder in fob to transfer as on the pcb.
- Battery fully charged and tested. Alternator charging it ok too.
- welded baulkhead and re-fitted bonnet hinge. Bonnet is now perfectly aligned and no movement (which may have been reason for previous mislock warning).
- The tailgate hinges were replaced as these had corroded through the pins and door dropped (another mislock warning contender).
- The rear offside door lock has failed. Specifically, the unlock solenoid has died.
- Lots of water was coming in through the perforated bulkhead and presumably getting into electrics in passenger footwell.
- Still have sunroof leaking which no doubt has meant water ingress of volumetric sensors.

Now, at the moment. The alarm has not gone off since locking up with key since fixing bonnet last week. Fingers crossed. I haven't yet trusted locking with the fob as I have a sickly neighbour that I don't wish to disturb if I can help it. BUT, I have a new twist that has emerged:

When I turn off the ignition, it wont start again unless I first remove the key and press the fob button to unlock. On doing so, the two green direction indicator lamps on the dash panel flash and I can then insert the key and start up. I get the same when I first unlock and try to start; as I turn the key the red alarm/imobiliser lamp glows steady and nothing happens. I have to remove the key, push the unlock button on the key fob to deactivate the imobiliser.

What is going on?

Sierrafery?

Why are you removing the key? Do u have to, to enable u press the lock button?
The indicators will flash when pressing unlock and lock, so no problem there.
If you delay starting the engine after unlocking the red LED will illuminate after a short delay indicating the engine has reimmobilised so no problem there.
And now back to the start, unlocking the vehicle will remobilise the engine so no problem.
So what exactly is happening?

Are u your saying is the engine doesn't stay remobilised for a short period after in locking? before the delay expires and the vehicle immobilise its self again..
Or the fob is not communicating with the "exciter ring arround the ignition switch, is that not happening?

I sustain discool's statements